[SB 291 

.14 14 

I Copy 1 



JTERNATIONAL BUREAU OF AMERICAN REPUBLICS 

JOHN BA.RRE1TT. DIREICTOR 
FRANQSCO J. YANES, SECRETARY 



RUBBER AND ITS RELATIVES 



(Reprint of an article from the Monthly Bulletin of the International 
Bureau of American Republics, December, 1 908) 




WASHINGTON. D. C. 
GOVERNMENT PRINTING OFFICE 

1909 



INTERNATIONAL BUREAU OF AMERICAN REPUBLICS 

' JOHN BARREITT. D I R El C T O R 

FRANCISCO J. YANES. SECRETARY 



RUBBER AND ITS RELATIVES 



(Reprint of an article from the Monthly Bulletin of the International 
Bureau of American Republics, December, 1908) 




WASHINGTON. D. C, 
GOVERNMENT PRINTING OFFICE 

1909 



^3 p ^ -. 






i i 



1/ r" 



RUBBP^R is one of the great essentials of modern industrial 
life. With iron or steel, Avith copper, and with glass it may 
be compared in the diversity of its use; it has the advantage 
over these, and may be compared in this latter resjDect to 
corn, wheat, and the necessary foods, in that it is capable of eternal 
reproduction if mankind will but apply to its cultivation his ex- 
perience and scientific knowledge. 

There is scarcely a device of daily commerce into which rubber 
does not enter as a necessity, and yet in the annual statistical publi- 
cation of the Department of Commerce and Labor — Commerce and 
Navigation of the United States — the student will look in vain for 
the word " rubber," and not until he examines the word or the phrase 
" indiarubber," " India rubber," or " India-rubber " will he be able 
to see how vast and important is the subject before him. This con- 
servatism — if the term may be here applied — is traceable throughout 
all the literature of all the libraries of the English-speaking world. 
The aboriginal native word describing the substance first discovered 
by the early Europeans was cahuchu., probably pronounced but 
surely corrupted into caoutchouc. This latter word has spread into 
the languages of Europe. In French it is the same word; in Ger- 
man the only modification is to substitute a k for the c^ and in Rus- 
sian nearly the same change takes place. To be sure the Spanish 
uses frequently the word goma.^ equivalent to our gum, and this is 
made more specific by adding the adjective elastica, and the Portu- 
guese has the word honrtcha, but caucho is commercially well un- 
derstood, as might be supposed from the first association with the 
source of suppl}'. Rubber, or India rubber, hoAvever, is undoubtedly 
the term which will continue to be employed in English to distin- 
guish this indispensable product of the Tropics. 

Caoutchouc directly explains the descent of the gum and its adop- 
tion into the arts, but India rubbei; embraces not only this history but 
conceals one of the romances *b'f:the industries. Travelers — and it 
is said Columbus himself AAas One of them — noticed that the Indian 
inhabitants of America, thought then to be an unknown portion of 
the Indies, played ball with a curious substance grown in the primi- 
tive forests and prepared according to native ways. This substance 
was also made into shoes; it formed a protective coating for gar- 
ments, and from it were made bottles which could be squeezed to- 
990 



JAIM 8 ?910 

fll [Mr il 



RUBBER AND ITS RELATIVES. 



991 



~' gether so as to eject the liquid contents. This substance was called 

caucho in some parts of America and the gatherers were cauclieros; 

^. in other parts the gatherers w^ere called, because of the shape of their 






■ - 

-m 


_^ 




i^??^* 








II 


nni 


mm 


IHHH 


nn^ 


K' 


.-* 







A RUBBER TREE OF THE CASTILLOA SPECIES. 

This tree, like its relatives, the fig, breadfruit, and the trumpet tree, has a general appearance and 
habit of growth whieh render it easy of recognition. The tree, with its rather smooth light-gray 
bark, has no striking peculiarities, but the slender, simple branches, with their large oval leaves, 
pendent in two rows, are similar to those of very few other trees. The Castilloa is native of Mexico 
and Central America, and thus far it has been supposed that its climatic and cultural requirements 
were quite different from those of the Para rubber tree, but it now appears that these differences 
have been greatly overestimated. 

bottles and the uses to which the Portuguese saw them put, seriii- 
gueiros, syringe men. From this origin the india prefix of the word 



992 



INTEKNATIONAL BUREAU OF THE AMERICAN REPUBLICS. 



is derived. At first the gum, goma elastlca, according to the Spanish, 
-was merely a curiosity: it was imported into Europe and studied 
chemically with great interest: it-:v\4vs made into tubes and put to 
practical use in the laboratory. But in IT TO the English chemist 
Priestley recommended the use of the gum for effacing the marks 
of the lead pencil. It rubbed out these marks and was therefore a 
rubber. It became more widely known as experiment showed its 
value, and in 1823 Macintosh discovered the method of waterproof- 




A RUBBER GATHERER IN TROPICAL MEXICO. 

The "Ulero," or rubber gatherer, is provided with a sharp wedge-pointed ax for tapping the tree, 
and gourds for conveying the milk to be coagulated. He is generally assigned a given territory. 
A good collector will gather from 15 to 20 pounds of rubber per day. 

ing garments, and added another word to the vocabulary. From 
this date india rubber Avas more and more an article of commerce; it 
served many purposes, but it also balked the inventors in many direc- 
tions in which they had hoped it might be applied. Experiments 
were constantly being made; even the incorporation of sulphur had 
been tried, but it was not until 1839 that Xelsox Goodyear, in the 
United States, hit upon a practical method of combining rubber with 



EUBBER AND ITS RELATIVES. 



993 



sulphur so as to retain all its ijooci, unique properties, while losing 
those that had made it hitherto unsuitable. This process was called 
vulcanization. 

Rubber — india rubber — is a definite chemical combination of car- 
bon and hydrogen, expressed by the (proportionate) formula C^ Hj., 
or CioHj,;. It is a whitish solid, opaque, scarcely reacted upon by the 
ordinary solvents, but forming fluid or gelatinous masses with the 
ethers and the coal-tar oils. All this refers, of course, to the chem- 
ically pure rubber. It will also melt and burn. Physically, rubber 
will stretch, and when tension is released its mass returns to the origi- 
nal position and form. Unfortunately, however, rubber in the pure 
state has three awkward qualities: It loses this distensibility at cer- 




vSCALE I EUROPE RUSSIA UNITED STATES 



aooCOOOLbS. fe.OOO.OOOLba. 12.000.0OO Lbs. I io.000.000 Lt>S7 



ms. 



RUBBER BOOTS— THE TRINCirAL BUT BY NO MEANS THE ONLY SOURCE OF 

" RECLAIMED RUBBER." 

Note.— Russia is not included in Europe, because it is attempted to show how great is the amount of 
rubber (from boots and shoes) reclaimed in Russia alone, as contrasted with the remaining portion 
of Europe. The cut illustrates the amount of old rubber shoes now held in various parts of the 
world, waiting to be turned into " reclaimexl rubber." 

tain degrees of heat and cold, it softens under heat, and has a great 
tendency to stick to itself or to other masses of rubber with which it 
is brought in contact. Noav, these three qualities of rubber as refined 
after entering the market from the tropical forests are overcome when 
it is mixed with sulphur— that is, vulcanized. It can then be molded 
into various shapes and still remain distensible. The degrees of tem- 
perature between which it retains these good qualities are very much 
wider apart, so that climatic changes are less felt by the manufactured 
product, and consequently rubber articles of an infiniteh^ more varied 
type can be turned out from the factories. Vulcanized rubber is 
therefore the substance really implied ordinarily by the word alone. 




COPY OF THE ORIGINAL ENGRAVING OF THE CASTILLOA ELASTICA, SOMEWHAT REDUCED. 

The rubber trees of Mexico received a botanical description and name in a paper read by Cervantes 
before the Royal Botanic Garden Association of the City of Mexico in 1794, and was printed on an 
engraved plate, a copy of which is in the Library of Congress, Washington. The tree was named 
Castilla in honor of Castilla, a Spanish botanist, who died in 1793, while engaged in the preparation 
of a work on the flora of Mexico. 



RUBBER AND ITS RELATIVES. 



995 



It might be thought that rubber woukl grow old after being once 
used in a manufactured article. So it does, but, almost like the met- 
als, it has a new life when restored to its earlier condition. Reclaimed 
rubber does not sell for as high a price as fresh rubber just imported, 
but it has a substantial value, and no discarded bit of rubber goods 
seems too old or Avorn-out for reclamation and repeated use in the 
arts. Up to a short time ago old rubber shoes seemed to be the only 




A RUBBER GATHERER IN BOLIVIA. 

The tapping of the tree marks the beginning of the rubber gatherer's work. He attaches a small cup 
to the tree, and with a wedge-shaped ax makes a gash in the bark, being careful not to penetrate 
the wood. This operation is repeated at intervals of about a foot in a line around the tree, until 
5 or 6 cups have been placed, into which the milk flows slowly. The next day a row of incisions is 
made just below the first, and so on until the ground is reached. A good tree will yield to a height 
of 20 feet or more. An expert gatherer can tap a hundred trees per day, provided they are close 
together. 

or principal source of supply for reclaimed rubber, but to-day, thanks 
to modern ingenuity in devising chemical processes by wdiich separa- 
tion is accomplished, rubber is extracted from belts, from hose, or 
from the scrap of the trade, devulcanized as far as possible, and re- 
turned to the manufacturer for further use, although in this state it 
is never so generally serviceable as fresh rubber. The departments 
of government, the railway companies, and large users of rubber 



996 



INTERNATIONAL BUREAU OF THE AMERICAN REPUBLICS. 



make a business of selling discarded articles, and rubber gatherers 
of the stuff vie with the cauehcros in supplying the market with the 
results of their labor. 

To one whose attention has not been carefully directed to the mat- 
ter the multiplicity of the uses and combinations of rubber will be 
astonishing. All know how common are rubber bands, lead-pencil 
eraser tips, stamps, and fountain 2)ens on a writing desk; every 
minute we see a wheeled vehicle fly past, its peace-destroying noise of 

yesterday obliterated by the rub- 
ber tire; but the use of rubber 
for these purposes, however enor- 
mous it is in the aggregate, by 
no means exhausts or even illus- 
trates the demands for rubber in 
modern industry. The devices 
into which rubber enters can no 
more be enumerated than can 
those of iron or copper, but 
among them may be mentioned 
the various appliances for insula- 
tion in electricity; without rub- 
ber an entirely neAv method of 
telegraphing and telephoning 
would have to be invented. The 
air brake of the railroad must 
have rubber for its proper equip- 
ment; our fire service would be 
essentially crippled without rub- 
ber in the hose, and, in fact, hose 
of any kind can scarcely be con- 
ceived without rubber. Packing, 
belting, and tubing imply the use 
of rubber. Then there are boots, 
rubber heels, and overshoes ; coats 
and gloves for clothing ; the many 
pharmaceutical, dental, and sur- 
gical rubber goods, such as blank- 
ets, stoppers, combs, sheeting, 
bandages, water bottles, and syringes. In domestic life there are 
carpets, mats, toys, and cushions; rubber paint and pavement have 
special advantages in selected places; roller skating would be a tor- 
ment, and English tennis, Scotch golf, and American baseball would 
be decidedly tamer without rubber. 

It is evident that there are two distinct phases to the study of this, 
commercial commodity. The one is industrial, the other botanical. 




COAGULATIXi; liri'.HKi: BY THK IS K OF 
MOON VINE JUICE IN MEXICO. 

The milk is emptied into this preparation, the 
impurities remaining in solution, and the 
clean rubber colleeting in a solid mass, which 
can be lifted off the top. 



RUBBER AKD ITS RELATIVES. 



997 



Before crude rubber becomes the finished product, it must be treated 
both mechanicall}^ and chemically to make it pliant for its multiform 
purposes. These processes are complicated, but necessary in trans- 
forming the raw material into an article ready for manipulation into 
any of the shapes mentioned above. First the rubber must be 
washed and cut into bits, then it is squeezed between rollers in order 
to remove the water and to prepare it in sheets; then it is dried and 
made ready for compounding. Ver}^ few articles as employed to- 
day are made of the pure gum ; 
some compound is necessary in 
many cases ; in others it is adopted 
in order to cheapen the price of the 
goods, which varies according to 
the quantity of compounded sub- 
stance used. The consumer can. 
however, if he wishes to pay the 
cost, get the best possible article, 
the judgment of the manufacturer 
alone determining how much rul)- 
ber to use. 

Sulphur is the principal ingre- 
dient employed in compounding 
rubber, and serves two purposes; 
it reduces the amount of pure rub- 
ber engaged for any article — in it- 
self a valuable item — and it is the 
most efficient vulcanizer known. 
It transforms pure rubber into two 
distinct commercial substances, ac- 
cording to the amount of sulphur 
used, but chiefly according to the 
intensity of heat applied to effect 
the combination, for in all proba- 
bilit}" a chemical change occurs 
here, in addition to the undoubted 
physical union of rubber with sul- 
phur. The one substance is soft 
rubber in the j^rotean elastic condi- 
tion familiar to all ; this is produced by combining pure rubber with 
sulphur at a low temperature. The other substance is hard rubber, 
ebonite, or vulcanite, in which all elasticity is lost, and the shape into 
which this is molded is permanently and rigidly retained, within 
natural temperature limits. Xevertheless, compounded and Aidcan- 
ized rubber will not last forever: it grows brittle and dull with age, 
the grittv scales on the surface of combs, etc.. beinw the crvstals of 




BASE OF TREE INJURED BY TAPPING. 

Anxiety to obtain tbe largest yield of rubber, 
with slight regard for the protection of the 
trees and for future production, has resulted 
in the permanent injury of many young trees 



998 



INTERNATIONAL BUREAU OF THE AMERICAN REPUBLICS. 



unabsorbed sulphur coming to the surface, so that vuk-anized rubber 
must finally be desulphurized and returned to the trade as reclaimed 
rubber. 

Millions have dreamed of the possibilities and fortunes have been 
premised as the result of a process producing a rubber substitute. 
Artificial or synthetic rubber would seem so easy ; take only ten atoms 
of carbon and combine them with only sixteen atoms of hydrogen 
and you have rubber. But the little trick of adding life to this inert 
molecule has not yet been learned. The fortune is still there for the 
lucky inventor who can accomplish it, because carbon and hydrogen 




COAGULATING THE LATEX IN MEXICO. 

1. Spreading the latex on Calathaea leaves. 2. Pressing the two coated leaves together to unite the 

sheets of rubber. 

are cheap, inexhaustible even, while rubber may get costlier year by 
year. The discussion of artificial rubber may therefore be dismissed 
with a phrase — there is no such thing. Either the exploited article is 
a humbug, or it contains some proportion of real rubber mixed with 
substitute ingredients. Rubber substitutes are often of value in the 
trade because the article manufactured from them only needs that 
small proportion of rubber they contain. 

The botanical aspects of rubber are, however, the more fascinating 
to the investigator, and touch very much more intimately the field 
in which the International Bureau of the American Republics is 



EUBBER AND ITS RELATIVES. 999 

interested. The plant from which the product comes is peculiarly a 
l^art of tropical flora, and although there are rubber-producing plants 
outside of tropical forests, the bulk of the staple is derived from 
a narrow belt on both sides of the equator, and decidedly better 
adapted in Latin America to rubber growth than corresponding 
regions elsewhere. 

Rubber is the cream from the juice, the milk, or the latex, of several 
varieties of tree or shrub. This latex is not the same as the sap, and 
it runs in different channels and performs different functions. As 
this latex flows from the cut in the tree, it has the appearance of milk 
and acts much in the same way. If left to itself, the latex separates 
into a lower fluid and a surface mass, like cream, which is india 
rubber. A latex possessing from 15 to 40 per cent of rubber (cream) 
is of value and will pay for working, but a proportion below this is 
poor and ^.hin, and only in exceptional circumstances will it return 
any profit. Various ways have been developed or devised for obtain- 
ing this rubber from the latex, the process being intrinsically coagu- 
lation. The aboriginal method seems to have been, in Brazil, by 
smoking heat ; elsewhere natural heat is applied, or mineral or chem- 
ical additions are made to the milk to separate the rubber. Recently 
the suggestion has been carried into practice of using the separator 
apparatus so efficient in the dairy industry. It can not be doubted 
but that the coagulation process adopted has a noticeable influence on 
the character and market price of crude rubber, although the kind 
of tree from which the latex flows, as well as the soil in which it 
grows, are substantial factors in the result. Having been, up to 
within recent times, largely a matter of native habit, left altogether 
in unscientific hands by the buyers of rubber, the coagulation showed 
remarkable differences, and in some instances has even impressed a 
name upon the product ; nigger heads, bisquits, and scraps are among 
the terms applied, but the shape of the crude rubber usually indicates 
the place from which it is shipj^ed. It will take years to uniformize 
the various native plans adopted for coagulation. Perhaps this will 
never be accomplished, but on plantations where careful study can 
be given to the matter it has been determined that heating by smoke 
produces the cleanest and purest rubber for commercial export. 

Rubber is rubber, whether from a tree on the Amazon, in the up- 
lands of Ceara, the mountains of Bolivia, the jungles of Nicaragua, 
the fastnesses of the Congo, the cultivated plantations of Ceylon, or 
the northern regions of Mexico; the important question is, however, 
whether the plant has an abundant yield of latex. Therefore the 
source of supply has been the subject of great study for the botanist 
ever since the first American discoverers saw the curious balls and 
bottles of the natives. 

The classification of rubber-bearing trees carries the number well 
toward one hundred, and if many latex-producting shrubs and vines 




TAPPING A RUBBER TREE IN CHIAPAS, MEXICO. 

The obiect in rubber tapping is not merely to avoid the destruction of trees, but to secure the 
maximum quantity of gum with the least injury to future productiveness The gatherer 
(uIi'to) makes with his machete. <liai,Miiial lines or gashes which form chaun<?ls m which the 
milk can llow'uutil it is all hroiiu-ht t.. one si.lr ni the tree, whence it is let down to a cavity 
hollowed in the ground and lined witli laivc lough leaves. These are dexterously lifted up, 
and the milk poured into a calabash or other vessel and carried away to be coagulated. 



RUBBER AND ITS RELATIVES. 



1001 



are included, the tale might be made threefold, but for practical pur- 
poses only four great species are recognized. The Euphorbiacese 
contain the Hevea and the Manihot; the UlmacCcT, the Cast'dloa and 
the Ficiis; the Apocynacea?, the Hancornia and the Landolphia; 
the Asclepiadese, Cynanchum. The six important trees are those 
under the first three varieties. 

Hevea is the rubber tree par excellence. It is indigenous to the 
region of the river Amazon, and is therefore found throughout that 
immense Avatershed in the tributary areas of Peru. Bolivia, Ecuador, 
Colombia, and Venezuela. Hevea is a large tree, of comparatively 







COAGULATING THE LATEX IN MEXICO. 

3. Stripping the leaves from the rubber. -1. A finished sample of rubber, marked by the veins of the 

leaves. 

slow growth, but on that account of long life. From the fourth year 
on it will yield its milk, and may be systematically tapped for twenty 
years or longer. It is often found 12 feet in circumference, and the 
scattered trees in the tropic jungle will constitute a forest by them- 
selves. The Hecea requires a low-lying, rich, deep soil, with such 
abundant moisture as only the equatorial neighborhood can give. 
Herea does not need to be overflowed; in fact, those trees that are 
subjected to periodic floods near the great rivers are not necessarily 
the best stock or the largest producers. Hevea also is well adapted 
to cultivation wherever the soil and climate are suitable, and the 
consensus of opinion is that in the ultimate future this tree, modified 



1002 INTERNATIONAL BUREAU OF THE AMERICAN REPUBLICS. 

perhaps by scientiiic- horticultiiiv, will 1k' the chief rubber bearer of 
commerce. This is the tree that has made Brazilian rubber famous, 
and for o:enerations to come Brazil is assured of a steady source of 
i-evenue from the supply furnished by this native of her fluvial 
forests. 

The Manihot tree produces the Ceara rubber of commerce. Its 
native locality is a high, stony, arid, and in places semidesert coun- 
try. Its latex yields a rubber remarkable for strength and tenacity, 




BRANCHES OF CASTILLOA ELASTICA WITH RIPE FRUIT. 

The fruit of the rubber tree has a faintly sweetish taste, btit is without appreciable flavor. It contains 
considerable milk, though not in commercial quantities. 

and promises to react successfully to cultivation if proper soil is 
selected for it, but as yet no efforts on a scale large enough for a 
thorough test have been attempted. 

The Castilloa, next to the Hevea, is the best-known rubber pro- 
ducer in the tropic belt. Its native habitat is Central America and 
southern Mexico, and it is found in Ecuador, Colombia, and Peru, 
having; been acclimatized also in the West Indies. The tree has at- 




PLANTED CASTILLOA ELASTICA TREES, ABOUT 14 YEARS OLD. 

This is a portion of a cultivated grove at La Zacualpa Plantation, Chiapas, Mexico. The scarred 
trunks show that they have been tapped many times. The trees average about a foot in diam- 
eter and stand about 12 feet apart in the rows. They were originally planted alternately with 
cacao, but this has mostly disappeared. 



1004 INTERNATIONAL BUREAU OF THE AMERICAN REPUBLICS. 

traeted considerable attention since the exploitation of rnbber planta- 
tions in the zones north of the eciuator, and is very adaptable to culti- 
vation if carefully treated. It is not so large as the Hevea^ nor is 
the latex the same, needing therefore quite different treatment in its 
coagulation; but that is a matter of science and art, which will be 
regulated as its characteristics become better known. This is the 
rubber tree that has been so butchered to supply the gi-owing de- 
mands of a consuming world. The natives, in their primitive zeal 
to extract the greatest possible amount of juice in the shortest pos- 
sible time, simply felled — killed — the tree and bled it to the last drop. 
Whole forests have been laid waste in the unrestrained search for 
rubber, but nowadays the principle of conservation has become 
firmly rooted and the tree must be well treated wherever it is still 
alive, while cultivation is restoring it to areas originally favorable to 
its propagation. The Ficus, the rubber tree of urban conservatories, 
is of the same genus with the CastiUoa, but its native habitat is the 
jungle of the eastern Tropics. In Assam, New Guinea, and the 
Malay Islands it is at home, but seems not to be of great profit when 
cultivated. It is likewise a tree of age, not coming to substantial 
yield until after many years of life, and therefore uni^romising to 
the proprietors of a rubber plantation, 

Hcuicornia is almost a shrub. It grows south of the Amazon 
Valley, and is found also in Venezuela and Peru ; in fact, it is one of 
the best-known sources of Peruvian rubber. It has, however, one 
fatal defect when considered as a plant for future usefulness; in 
order to get the latex the tree must be cut down. Although more 
intimate acquaintance may determine that Tlancornia can be culti- 
vated, and, acknowledging that its rul)ber product ranks well up in 
the scale, it is probable that the area in which the tree now grows, 
if the culture be continued, will be planted with Herea or CastiJloa^ 
according to the soil. 

Landolphia (Lianas) is a rubber-yielding vine growing in the 
jungles of the Far East, of New Guinea, and especially of Africa 
in the basin of the Congo. Its product is commercially of decided 
value, but the fear that it may depress the native industry of Latin 
America or the cultivated plantations of Ceylon is groundless, be- 
cause, however extensive may be the territory over which the vine 
is found, it must be destroyed in order to extract the latex ; and culti- 
vation is out of the question, since the vine requires the support of 
forest trees for its growth, and no plantation can first cultivate a 
sunless jungle before introducing a commercial staple. 'N^Hien the 
indigenous vine becomes exhausted the land on which it appeared 
must be diverted to other crops. 



RUBBER AND ITS RELATIVES. 



1005 



Considering the immense and increasing use of rubber in modern 
life, it is a fascinating problem to estimate how great may be the 
rubber-producing area of the world. It can be assumed that the genu- 
ine rubber tree will not repay the cost of cultivation outside of a 




A RUBBER-PRODUCING MISTLETOE IN VENEZUELA. 

Though not Yielding a commercial rubber, this parasitical growth,. like many leguminous plan^^^^^^ 
shrubs in tropical countries, produces a gummy exudation very similar to good rubber, but lacking 
the essential property of elasticity. 

zone lying about 500 miles on either side of the equator. This in- 
cludes all the .Amazon basin in Brazil, the greater portion of Peru, 
the northern section of Bolivia, all of Ecuador, Colombia, Venezuela, 
Panama. Central America, and the southern section of Mexico. In 

62684— Bull. 6, pt 1—08 5 



1006 INTERNATIONAL BUREAU OF THE AMERICAN REPUBLICS. 

Africa it includes the Congo basin and the Sudan on the Avest, and 
the analogous portion on the east; in Asia the larger part of India, 
the northern tip of Australia, the intervening archipelagoes, and 
the Philippine Islands. No one can calculate with precision the 
productive extent of these regions, because the deciding factors of 



ll\ubhar. 



BLACK SpUAI?t SHOWS 
CULTIVATED AREA 

l-ARGt BLOCK 3H0W3 
■ UHCUTtVATED AIJEA 




PROPORTION OF CULTIVATED AND 
UNCULTIVATXD AREAS ~ 



POUNDS - I90£ 



^ 5 0. 000.000 



1903 



1904 



1905 - 1906 



i 25.000.000 



zoo ooo.ooo 



1 7S.000.000 



ISO. OOP. OOP 



12.5.000.000 I 




• CONSUMPTION ^-J^ PRODUCXION* 

r 



KoTE. — Consumption and production are here taken as synonymous with imports and exports, because 
practically no producing country manufactures rubber, and no consuming country has rubber 
lands. It is impossible, likewise, to make imports and exports balance, and this explains the con- 
tinued preponderance of consumption over production. As a matter of fact, this relationship, 
although actually maintained, is less than the diagram indicates, because a noticeable amount of 
reclaimed rubber is annually added to the new rubber just entering the market. 

soil, rainfall, elevation, drainage, moisture, and temperature are not 
enough known ; nevertheless, the area absolutely available is so well 
understood that any fear of a rubber famine, so far as nature's ability 
is concerned, is unfounded. Rubber cultivation has already extended 
over 150,000 acres in Ceylon; in the Federated Malay States are 



KUBBER AND ITS RELATIVES. 



1007 



130,000 acres; elsewhere in the East are at least 30,000 more; so that, 
even where it has been artificially introduced into an alien land, all 
told perhaps 600,000 acres, the tree itself is doing its duty in supply- 
ino- the wants of mankind. In the western continent, Mexico and 
Central America are extending the cultivated territory for the plant, 
while experiments are making in other parts of the world. In Cuba 
and the Philippines there are extensive sections adapted, in all se- 
curity, to the propagation of rubber. Cultivation, therefore, if con- 




( Reproduced from India Rubber World.) 



AN EXPANSE OF GUAYULE LAND. 



The guavule shrub is found over large areas of the chaparrales, or bush prairies, in the northern part 
of the Mexican highlands. The first reports concerning this plant and its value are said to have 
been made by a Jesuit priest, about the middle of the eighteenth century. The name is probably 
derived from the Spanish word Hay (there is), and the Indian word Hide, meaning india-rubber. 

ducted scientifically, can furnish the supply. It is not intended to 
ignore the future productive possibilities of the native forests. In 
Mexico and Central America the rubber zone is, from the configura- 
tion of the country, within reach; but in the Amazon Valley thou- 
sands of square miles are hidden beneath the virgin forest, and how- 
ever inexhaustible the growth of the tree, the acquisition of the rub- 
ber, difficult at present, wall become more and more so as time goes on. 
That this is the natural habitat of the Hevea can not be doubted, but 



1008 INTERNATIONAL BUREAU OF THE AMERICAN REPUBLICS. 

that it Avill continue to remain the principal source of supply has 
been questioned by students and observers ever since Ceylon made a 
successful i:)lantation of this tree in 1877. The Brazilian and other 
governments are earnestly striving to conserve the rubber forests, to 
rectify earlier mistakes in the way of unrestrained robbery, and to 
encourage not only the entrance of more cajoital into the industry, but 
to bring into cultivation and make more accessible the area already 
exploited. Nevertheless, it is not beyond possibility that in this in- 




(ReproduL'cd from India Kubbc-r World.) 



A BALE OP GUAYULE SHRUB. 

Within the few years since the exploitation of the guayule plant began, Mexico has arisen to second 
place among the rubber-producing countries of the world. The United States talies 80 per cent of 
the annual production. 

stance the same result may happen as did happen with cinchona. 
This is still known to the pharmacopoeia as Peruvian bark, but the 
industry has moved thousands of miles away from its native birth- 
place, and the supply of quinine, as far as the commercial market is 
concerned, now comes from India. 

Be all this as it may, Brazil — ^Manaos, Para, Ceara — continues to 
dominate the india-rubber world. Assuming the world's last an- 



RUBBER AND ITS RELATIVES. 



1009 



mial crop to be 150,000,000 pounds, her exports in 1907 were over 
80,000,000 pounds. Add to this the Peruvian and Bolivian crops 
coming down the Amazon, and considering that fine Para sets the 
price, it will be seen that many years must pass before the predomi- 
nance can be overcome. This product was sent to the United States, 
Great Britain, France, Germany, Urugua3% Belgium, and Argentina, 
in this order. It is easy to understand that Belgium ranks low in 
importation from Brazil, because the output from the Congo has its 
chief entrepot in Antwerp. The markets for the world's crop may 
be arranged as follows : The United States, Great Britain, Germany, 
France, and Belgium. 




(Reproduced from India Rubber World.) 

FOUR HUNDRED TONS OP GUAYULE RUBBER. 

These bales vary in weight from 70 to 1') pounds. During the calendar year 1907 guayule rubber 
exports from Mexico reached a total of il, 900,000 pounds, and for the hrst six months of 1908 nearly 
7,000,000 pounds. 

Guayule is a shrub containing rubber in its branches, but this 
rubber is pure rubber and can be used for every purpose to which 
the latex of the Ilei'ea is applied. Guayule therefore contradicts 
the statement made that no rubber could be produced outside the 
tropic zone. Guayule is a native of Mexico, but its habitat stretches 
also well into Texas. The shrub must be destroyed before the juice 
is extracted, and coagulation must be conducted by a different 
method, but in the end the outcome is rubber. The business of gath- 
ering the plant has become quite successful, and it is probable that 
efforts to cultivate it will turn out likewise. Gutta percha is not 
rubber; it was at first confused with the latter, although it had no 



lOiO INTERNATIONAL BUREAU OF THE AMERICAN REPUBLICS. 

suppleness or elasticity, and its source of origin is a tree related to 
the india-rubber genus, but physically it has different properties, and 
in the arts it has different uses. About all the gutta percha of com- 
merce comes from the Far East. Bulata is an American gutta percha, 
growing in many i^arts of the Tropics, but produced chiefly in Venez- 
uela and the (xuianas. A practical distinction between rubber and 
gutta is found in the (Latin) names, gummieum elasticum for rub- 
ber and (jinnmk'iim plasticvm, for gutta. This substance has two 
important uses; one is for insulation in telegraph instruments, but 
l^articularly for covering to submarine cables, which it protects bet- 
ter than any known substance against the water or the animal attacks 
beneath the surface ; the second is for forming molds of various 
kinds by surgeons and dentists. It plays also a part in the manufac- 
ture of golf balls. At least 1,000 tons a year of giitta percha have 
been used since 1858 in submarine cables, the length of which has 
reached over 200,000 miles. 




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